1. Field of the Invention
The present invention relates to a magnetic card comprising a substrate, and a magnetic layer provided thereon, in which information is magnetically recorded in such a manner that the recorded information can be mechanically read.
2. Description of Related Art
A magnetic card is produced by providing, on a substrate, a magnetic layer in which the ID number of the user of the card, and the like are magnetically recorded in such a manner that the recorded data can be mechanically read. Magnetic cards of this type are widely used as bank cards, credit cards, and the like.
It has conventionally been known that the magnetic layer is concealed in order to ensure the security of the magnetic card. Conventional methods for concealing the magnetic layer are as follows:
a first method in which a specific ink is applied, by means of printing, to the entire surface of the substrate including the surface of the magnetic layer provided on the substrate, thereby concealing the magnetic layer; PA1 a second method in which an ink is applied, by means of printing, to the surface of the magnetic layer provided on the substrate, wherein the color of the ink is the same as that of the substrate, thereby concealing the magnetic layer; and PA1 a third method in which an ink is applied, by means of printing, to the surface of the substrate excluding the surface of the magnetic layer provided on the substrate, wherein the color (dark color) of the ink is the same as that of the magnetic layer, thereby concealing the magnetic layer.
However, the conventional magnetic cards have had the following problem. Namely, when the thickness of the ink layer which is provided on the magnetic layer by means of printing is increased, the magnetic output of the magnetic layer is lowered, so that reading errors can be made when the information recorded in the magnetic layer is read. Under the circumstances, it has been impossible to form, on the magnetic layer by means of printing, an ink layer whose thickness is larger than approximately 6 micrometers. Therefore, there has been such a problem that, when an ink is applied to the magnetic layer by means of printing to conceal the magnetic layer by the above-described first or second method, and when patterns, etc. are further printed on the surface of this ink layer, the number of colors which can be used for printing the patterns, etc. is limited.
On the other hand, in the case of the above third method, an ink is not applied to the surface of the magnetic layer by means of printing, so that this method is free from the aforementioned problem. However, the card produced by the third method is entirely darkish in color. The design of the card is therefore restricted.